Audio amplifier



FIG. 1 is a perspective view of an audio amplifier according to the present invention;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a left side elevational view thereof; the right side being a mirror image of the left side; and,

FIG. 6 is a rear elevational view thereof. 

The ornamental design for an audio amplifier, as shown and described. 